Improvement in the manufacture of tin foil or sheets



UNITED STATES PATENT OFFICE.

JOHN-J. OROOKE, on NEW YORK, N. Y.

IMPROVEMENT lN THE MANUFACTURE OF TIN FOIL 0R SHEETS.

Specification forming part of Lettcrs Patent No. 10,501, dated February 7, 1854.

To all whom it may concern:

Be it known that I, JOHN J. GRooKE, of the city, county, and State of New York, have invented certain new and useful Improvements in the Manufacture of Tin Foils or Sheets; and I do hereby declare that the following is a full, clear, and exact description of the same.

My invention consists in such improvement in the manufacture of tin foils or sheets that by it I accomplish the reduction of the. cost, though retaining those qualities which are essential to the purposes for which such foil or metal is required. This '1 effect by combining the baser and cheapermetal, lead, with the tin, not, however, in the form of an alloyor mixture, but so that each metal will be kept perfectly distinct, the tin or superior metal being only exposed, while the lead or inferior metal is incased within. In order to make such sheets or foils, a peculiar ingot or slab must be first made, by which the whole amount of metals to be contained in the intended sheet or foil must be joined at their surfaces and retained in such position that'the subsequent action of the rolls shall not be able to displace or extend one metal more rapidly than the other, for it is evident that the lead, by reason of its being the softer and more yielding metal, would be squeezed out in an undue proportion to the tin were it not confined on all sides by the tin. I therefore make the ingot or slab for rolling in the following manner: First, a metallic mold is made which shall determine the size of the slab to be cast. The cavityin such mold may he, say, six inches wide, one inch thick, and teninches long. Then prepare a slab of lead as much less in size than the cavity in the mold as is designed for the different proportions of the metals, say, of the following dimensions: five and one-half inches wide, nine and onehalfinches long, and half of one inch thick. This, when suspended in the center of the mold, will leave a clear space all round, and the tin can then be poured in. To accomplish this suspension properly I prepare small blocks or posts of tin of a length equal to the space left between the lead and the sides of the mold, and by placing these around on all sides I sustain the slab of lead exactly in the center. The surface of the lead being properly clean,

or properly fluxed or coated with an alloy of lead'and tin, the mold is ready to receive the tin, which is poured in until 'the whole of the space is filled, the lead being then completely inc-.ised within it. The posts of tin of course combine with the fluid tin poured in and form part of the solid mass. The slab is now ready for the rolls, and may be extended into sheets and foils of any degree of thinness. From this construction of the slab or ingot it is evident that the lead cannot escape from the tin, but mustextend and be pressed out with it in exactly the same manner and at the same rate, thus insuring perfect equality in regard to the given proportions first adopted as to every part of the sheet, no one partthaving more lead in combination with it than another. Thus foils or sheets are produced which for many of the purposes to which those of pure tin are applied-such as for wrappers of tobacco, caps for bottles, Sac-are fully equal in the qualities required to thoseof pure tin, while they are furnished at a greatly reduced cost.

What I claim as of my invention and im' provement, and desire to secure by Letters Patent, is-

The new article of manufacture herein described-that is to say, sheets or foils composed of tin and lead formed in separate strata, but so that the exposed or external surface shall be pure tin only, for the purposes and substantiallyin the manner set forth.

JOHN J. GROOKE.

Witnesses:

'S. H. MAYNARD, J AS. L. ROBERTS. 

